New Super Mario Bros. 2 Cheats For 3DS

Unlimited 1ups

Same as Mario on the NES. Go to Mushroom World course 1, the place where the first star coin is.
Stand on top of the stairs and wait for the koopa troopa. Go down to the second or third step and wait for the koopa to reach you. Jump on it lightly (not hitting jump when you hit it) and then it should bounce off the wall and Mario will keep jumping on it, allowing you to get 3 crowns in a few minutes.
Note - If you try this as Golden Mario, the koopa will disappear after 25 hits.

Mario loses his hat

Play as Luigi

To play as Luigi in the game's single player mode, you must first finish the game by beating Bowser in World 6. After you do that, when on the file select screen, hold down the L and R buttons while selecting a file with the A button. Luigi will now be your selected character.

Second Title Screen

Secret Rainbow Levels

In order to gain access to the secret rainbow levels, you have to jump on the flagpole when the timer shows the correct time.
If done correctly, you'll hear the original NES world-cleared-jingle followed by a firework and a rainbow.
When you return to the world map, the entrance to the secret rainbow level will appear at the entry point of each world on the far left.
Secret rainbow levels contain no enemies but hundreds of coins and eventually golden flower power-ups.

Unlimited-Use Toad Houses

After beating every level of the game, all of the Toad Houses in the game - even if previously already used - can be reused, and reused as much as desired, allowing you to get power-ups and 1-Ups any time you need them.